Provide chrome the option of learning the debug stub port chosen by nacl.

src/trusted/debug_stub/transport_common.cc

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <algorithm>
 #include <string>
 
 #include "native_client/src/include/nacl_scoped_ptr.h"
 #include "native_client/src/include/portability_sockets.h"
 #include "native_client/src/shared/platform/nacl_log.h"
 #include "native_client/src/trusted/debug_stub/platform.h"
 #include "native_client/src/trusted/debug_stub/transport.h"
 #include "native_client/src/trusted/debug_stub/util.h"
 #include "native_client/src/trusted/service_runtime/sel_ldr.h"
 
 using gdb_rsp::stringvec;
 using gdb_rsp::StringSplit;
 
+#if NACL_WINDOWS
+typedef int socklen_t;
+#endif
+
 namespace port {
 
-typedef int socklen_t;
-
 class Transport : public ITransport {
  public:
   Transport()
     : buf_(new char[kBufSize]),
       pos_(0),
       size_(0) {
     handle_ = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
 #if NACL_WINDOWS
     CreateSocketEvent();
 #endif
@@ skipping 377 matching lines @@
     if (setsockopt(socket, IPPROTO_TCP, TCP_NODELAY,
                    reinterpret_cast<char *>(&nodelay),
                    sizeof(nodelay))) {
       NaClLog(LOG_WARNING, "Failed to set TCP_NODELAY option.\n");
     }
     return new Transport(socket);
   }
   return NULL;
 }
 
+uint16_t SocketBinding::GetBoundPort() {
+  struct sockaddr_in saddr;
+  struct sockaddr *psaddr = reinterpret_cast<struct sockaddr *>(&saddr);
+  // Clearing sockaddr_in first appears to be necessary on Mac OS X.
+  memset(&saddr, 0, sizeof(saddr));
+  socklen_t addrlen = static_cast<socklen_t>(sizeof(saddr));
+  if (::getsockname(socket_handle_, psaddr, &addrlen)) {
+    NaClLog(LOG_ERROR, "Failed to retrieve bound address.\n");
+    return 0;
+  }
+  return ntohs(saddr.sin_port);
+}
+
 }  // namespace port